View Full Version : Render just the shadows?

10-15-2002, 12:11 AM
Hello again!

How do I do to render only the shadows into a alpha canel that I can import in to Photoshop?

Thanks for all the help! :D

10-15-2002, 12:18 AM
it'd kinda help to know what version of LightWave you are using.

10-15-2002, 12:47 AM
Lightwave 7.5

Can I also render some reflections in alpha (half transparent)

10-15-2002, 01:52 AM
for reflections, you'd probably have to do it on a per-object basis. make the object pitch black, luminosity 0%, diffuse 0%, 0% everything that won't affect the reflection (keep bump, etc.) and set all surfaces except the reflecting one to NOT affect the alpha. then you can use the alpha to cut out the reflecting object only.

for shadows, make all surfaces completely white, 100% diffuse, 0% everything else that won't affect shadows (keep transparency, for example). depending on what shadows you want (self shadow, cast shadow, recieve shadow), you'd change these settings for all objects. with this, you should only recieve shadows in the render.

10-15-2002, 06:44 AM
mmmh, you could use the buffer exporter...

easyest way to do that: use PDS export, (under IMAGE FILTERS, Ctrl+F8) you can choose to export depth buffer, spec, shadow etc...

doesn't export radiosity shadow though (but it saves the "real" rendering so that's not really a problem...)

10-15-2002, 12:34 PM
Dies-irae means the PhotoShop PSD Exporter.

10-15-2002, 05:32 PM
For alpha shadows - just go to Surface editor -> Advance tub here u have options for alpha channel. The "Surface opacity" is default, change this to "Shadow density" - that's all.

10-15-2002, 05:59 PM

I have a picture of the rendered image and one on the shadow, but the shadow isnīt smooth and when I open it in Photoshop it hasnīt any alpha.

How should I work with it to get the right color and alpha?

Here are the pictur (I know itīs to light and that itīs a bad quality)

10-15-2002, 07:34 PM
It's work with all types of lights and with all types of shadow. For colored shadow use "Shadow color" option (only 7.5).
This image is PNG with alpha. This method don't work with radisity only ...
Also check the what format u save - any 32 bit format (TGA, TIFF, PNG and others) will save alpha.

10-15-2002, 07:35 PM
Opps... no alpha :)
Here is alpha only.

10-15-2002, 07:51 PM
Thak you very much!!! :applause:

PNG exports alpha, as you said but when do you use the alpha file?

Is there any way to create the reflections easaly to?

Once again... Thank you! :applause:

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